Nitsche's method was originally introduced in [1]} to weakly enforce Dirichlet boundary conditions.
Its application to the unilateral contact problem considered in this paper was originally proposed in [2]}, where the well-posedness and convergence of a conforming finite element scheme are studied.
Further extensions to problems involving friction or multiple bodies can be found in [3]}, [4]}, [5]}, [6]};
we also mention [7]} concerning the adaptation of these ideas to Hybrid High-Order discretizations [8]}, [9]}, [10]}.
A residual-based a posteriori error analysis can be found in [11]} based on a saturation assumption.
